Migration patterns, use of stopover areas, and austral summer movements of Swainson's hawks

The Condor
By: , and 



From 1995 to 1998, we tracked movements of adult Swainson's Hawks (Buteo swainsoni), using satellite telemetry to characterize migration, important stopover areas, and movements in the austral summer. We tagged 46 hawks from July to September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson's Hawks followed three basic routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal area in central Argentina for the austral summer. North of 20° N, southward and northward tracks differed little for individuals from east of the continental divide but differed greatly (up to 1700 km) for individuals from west of the continental divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. Southbound migration lasted 42 to 98 days, northbound migration 51 to 82 days. Southbound, 36% of the Swainson's Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio-marked hawks and made stopovers 9.0–26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and north-central Mexico. The birds stayed in their nonbreeding range for 76 to 128 days. All used a core area in central Argentina within 23% of the 738 800-km2 austral summer range, where they frequently moved long distances (up to 1600 km). Conservation of Swainson's Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons, including migration stopovers.

Publication type Article
Publication Subtype Journal Article
Title Migration patterns, use of stopover areas, and austral summer movements of Swainson's hawks
Series title The Condor
DOI 10.1525/cond.2011.090243
Volume 113
Issue 1
Year Published 2011
Language English
Publisher The Cooper Ornithological Society
Publisher location Waco, TX
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 18 p.
First page 89
Last page 106
Time Range Start 1995-01-01
Time Range End 1998-12-31
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